Gas distributor

ABSTRACT

A conical chamber having a serrated bottom edge is provided with a centrally and upwardly supported bottom plate in order to distribute gas bubbles throughout a liquid when a gas is introduced under pressure into the chamber. In one embodiment, a second plate contacting the inner wall of the conical chamber, or an annular ledge formed thereon, acts as a check valve in the event of a gas pressure failure. In another embodiment, a resilient sleeve fitted about a gas inlet pipe having only circumferential openings acts as the check valve.

United States Patent 1191 Piper GAS DISTRIBUTOR [75] Inventor: Louis H.Piper, Richmond, Va.

[73] Assignee: Westinghouse Electric Corporation,

Pittsburgh, Pa.

221 Filed: Feb. 18, 1971 211 Appl. No.: 116,495

[52] US. Cl. 261/124, 239/534 [51] Int. Cl B0lf 3/04 [58] Field ofSearch 261/121 R, 124; 239/534 [56] References Cited UNITED STATESPATENTS 3,294,380 12/1966 Born 261/121 2,603,465 7/1952 Malzacher 261/142,476,320 7/1949 Paulus 137/5255 X 3,179,124 4/1965 Haring l37/516.11

3,334,819 8/1967 Olavson 239/534 2,106,775 2/1938 Trask 230/221 [451Aug. 28, 1973 2,986,383 5/1961 Lowry 261/124 2,402,132 6/1946 Goldberg261/124 3,608,334 9/1971 MacLaren 137/5253 X Primary Examiner-Jim R.Miles Assistant Examiner-William Cuchlinski, Jr. Attorney-A. T.Stratton, Z. L. Dermer and M. B. L.

l-lepps [57] ABSTRACT A conical chamber having a serrated bottom edge isprovided with a centrally and upwardly supported bottom plate in orderto distribute gas bubbles throughout a liquid when a gas is introducedunder pressure into the chamber. In one embodiment, a second platecontacting the inner wall of the conical chamber, or an annular ledgeformed thereon, acts as a check valve in the event ofa gas pressurefailure. In another embodiment, a resilient sleeve fitted about a gasinlet pipe having only circumferential openings acts as the check valve.

6 Claims, 5 Drawing Figures Patented -Aug. 28, 1973 3,754,740

2 Sheets-Sheet l WITNESSES INVENTOR f4 5 Louis H. Piper I GASDISTRIBUTOR BACKGROUND OF THE INVENTION This invention pertains to gasdiffusers and more particularly to mechanical diffusers provided with aplurality of small openings through which gas bubbles may pass.

In sewage or water treatment units, aeration is utilized to provideoxidation and circulation within the treatment tank. Oxidation andcirculation proceed more efficiently where a uniform pattern of smallair bubbles are continuously produced proximate the bottom of such atank.

Methods for introducing gas into sewage and waste water generally fallinto the category of (l) diffuser aeration systems wherein air underpressure is delivered to a diffuser which introduces the air as finebubbles into the liquid and (2) mechanical aeration system whereinentrainment of oxygen is achieved by agitating the liquid with arotating impeller device which promotes contact between atmosphere inair and the liquid undergoing treatment.

For many years, porous media diffusers made of ceramic stone or bondedaluminum oxide were the most widely accepted means of introducing air orgas into waste liquid, but due to problems of clogging, they have beengenerally replaced by either mechanical surface type aerators orcompressed air diffusers utilizing a mechanical means such as aperforated pipe to produce the small air bubbles required. Mechanicalaerators are high in first cost and although quite efficient requireconstant maintenance. Perforated pipe diffusers, although lessexpensive, have often been inefficient in transferring oxygen into aliquid, moreover, such diffusers also suffer from the problem ofclogging Clogging results from debris accumulation either within thebubble producing openings in a diffuser or due to debris accumulation inthe body of the diffuser itself. A major source of debris accumulationis a failure of the pressurized gas supply s'ystemfIn the event of sucha failure, liquid would normally fill the internal chamber within thegas distribution device carrying with it any suspended solids; whichafter repeated gas supply failure could partially fill the chamber andclog the gas diffusion holes.

SUMMARY OF THE INVENTION Debris accumulation within the internalstructure including the gas distribution openings of a diffuser isminimized in accordance with this invention by the provision of a checkvalve type structure within the body of the diffuser.

The diffuser itself comprises a generally conical chamber having aserrated bottom edge. A relatively stiff bottom plate is laterallysupported by the gas inlet conduit between a locking nut and an annularledge formed on the inlet conduit. The bottom plate extends across thebottom of the conical chamber to within a small distance of theperiphery. The gas inlet line has a plurality of circumferentialopenings through which gas gains ingress to the conical chamber formedwithin the diffuser. The gas then proceeds through the openings formedby the serrated bottom edges of the conical structure and the bottomplate so as to produce a plurality of small bubbles uniformly spacedabout the periphery of the chamber.

In one embodiment of the invention, a second rela tively flexible plateis situated contacting the bottom plate and against the annular ledgeformed in the gas inlet line and extends outwardly so as to firmlycontact the inner surface of the conical chamber, or an annular ledgeformed thereon. This plate or formed diaphragm may be flat or slightlydished at at edge so as to provide firm contact with the inner surfaceupon which it seats. Normally the air pressure causes the gas to escapearound the edges of this diaphragm. However, in the event of a gasfailure, the diaphragm, because of its resilience, firmly seats againstthe annular ledge of the conical chamber so as to prohibit fluid andmore specifically the debris carried therein, from entering theinterstices of the conical chamber.

In a second embodiment, a resilient sleeve is placed around a portion ofthe gas inlet pipe internal of the conical chamber so as to normallycover the circumferential opening through which gas enters the conicalchamber. The resilience of the sleeve allows the gas to expand to enterthe conical chamber from which it escapes through the serrated openings.However, in the event of gas failure, the resilient sleeve closes offthese openings so that fluid and debris cannot enter the gas inletlines.

DESCRIPTION OF THE DRAWINGS For a better understanding of the invention,reference may be had to the accompanying illustration embodiments, inwhich:

FIG. 1 shows an embodiment of a gas diffuser in accordance with thisinvention;

FIG. 2 shows a sectional view along line IIII of FIG.

FIG. 3 shows a sectional view along line III-III of FIG. 1;

FIG. 4 shows a second embodiment of the diffuser having a differentcheck valve structure therein; and

FIG. 5 shows a suitable system for utilizing the diffusers depicted inthe previous figures.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. I, there isshown a diffuser 10 of a design suitable for both providing oxidationand circulation within a treatment tank 2. The diffuser system of FIG. 5generally includes a source of gas pressure (not shown) and a conduit 4which conveys thegas to a manifold 6. A plurality of diffusers 10 arecoupled to a single manifold 6. The gas supply arrangement depicted isshown and described in greater detail in a copending application Ser.No. 108,041, filed Jan. 20, 1971 by L. A. McKinney on a Method andApparatus for Gas Diffusion. The diffusers 10 are mounted verticallyabove the manifold 6.

The diffuser 10 is preferably constructed from a small number of easilyformed parts which can be readily assembled and disassembled. Theumbrella I2 of the diffuser 10 is preferably formed as a single unit ofa generally wide-angled conical form. Its apex is closed by a stem 14which can be simply cemented to the umbrella 12. The stem 14 is formedintegral with and as an extension of an inlet pipe 16. The inlet pipe 16has a central bore 20 and a plurality of circumferential openings 22through which a gas, such as air in the case of sewage aeration, can befed to a chamber 24 formed within the umbrella l2.

A disc 30 of a relatively stiff material such as metal or fiber glasspreferably extends substantially but not entirely across the mouth ofthe chamber 24. The cooperattive association of the diamond shapedserrations 28 in the umbrella l2 and the disc 30 form gas channels 32through which gas may pass into a liquid in the form of relatively smallbubbles. The size of the bubbles formed is determined by both thetriangular channels 32 left between the periphery of the disc 30 and theoutward apex of the diamond shaped serrations 28 and the gas pressurewithin the chamber 24. lncreasing gas pressures tend to lift the edge ofthe disc 30 so as to expand the triangular gaps or openings 32.

As previously indicated, both the interstices of the chamber 24 and theopenings 32 can be clogged by debris accumulation due to liquid andparticle ingress upon repeated gas pressure failures. A check valvestructure including a diaphragm 34 of a flexible material such as rubberor soft plastic, and, where desired, an annular ledge 36, formed on theinner wall of the umbrella 12, is utilized to prohibit such ingress ofparticles. In the event of a pressure failure, the diaphragm 34 isbiased to seat against the ledge 36.

The disc 30 and the diaphragm 34 are provided with centrally locatedopenings 38 and 48, respectively, so

that these members, 30 and 34, can be slipped over the pipe 16. Themembers, 30 and 34, are butted against an outwardly protruding annularflange 50 on the pipe 16 and a locknut 52 is screwed tight against thedisc 30 to hold the members, 30 and 34, in their desired positions.

As an alternate to the above scheme, the diaphragm 34 may be replaced bya resilient sleeve 54; see FIG. 4, where like numerals designate similarstructure. The flange 50 in this embodiment is inwardly extending suchthat the portion of the pipe 16 which contains the circumferentialopenings 22 is of uniform diameter. The sleeve 54 is filtered about andis substantially coextensive with this portion.

The sleeve 53 which may be made of rubber is expanded to allow egress ofgas as long as the pressure in pipe 16 is greater than that withinchamber 24. However, in the event of a pressure failure, the sleeve 54is forced against the pipe 16 so as to seal the openings 22 and preventingress of liquid and particles into the pipe 16.

As previously described, a plurality of diffusers 10 may be suppliedwith gas from a single source through one or more manifolds 6. Shouldthe pressure in a manifold 6 be inadvertently reduced, all of thediffusers 10 are prevented from debris accumulation by the check valvestructures integrally associated with each diffuser 10.

Therefore, I claim:

1. A gas distribution nozzle comprising, in combination:

a hollow body formed of a generally conical umbrella like member, saidmember being closed at its apex and open at the end opposite the apex ofthe conical form to provide a gas outlet adjacent said open end,

a relatively stiff bottom plate normally biased against the peripheraledge of said member;

conduit means within said hollow body for connec tion to a source of gaspressure; and

a check valve member internal of the hollow body positioned intermediatesaid conduit means and said outlet.

2. The gas distribution nozzle of claim 1 including a plurality ofserrated opening formed in the peripheral edge of the umbrella-likemember.

3. The gas distribution nozzle of claim 2 wherein the internal angleformed within the conical wall of the hollow body is relatively wide andthe bottom plate is within the periphery of the conical member.

4. The gas distribution nozzle of claim 2 including a relativelyresilient plate supported within the conical member inwardly of andadjacent said bottom plate, an annular ledge formed on the inner wall ofthe conical member, and means biasing the resilient plate against theannular ledge and said bottom plate positioned to limit the movement ofsaid resilient plate away from said ledge.

5. The gas distribution nozzle of claim 2 wherein said conduit meanscomprises a pipe protruding throulh the bottom plate and having onlycircumferential openings and including a resilient sleeve fitted aboutthe portion of the pipe having said openings so as to seal said openingswhenever sufficient pressure does not exist to expand said sleeve.

6. A gas distribution system for providing oxidation and circulationwithin a fluid including:

a tank;

a source of gas pressure mounted proximate said tank;

' a manifold supported within said tank and flowcoupled to said sourcethrough a conduit extending therebetween;

a plurality of diffusers mounted on said manifold and having conduitmeans therein respectively adapted to be supplied with a pressurized gastherefrom, each said diffuser comprising a hollow body formed of agenerally conical umbrella-like memher, said member being closed at itsapex and open at the end opposite the apex of the conical member toprovide a gas outlet adjacent said open end,

a relatively stiff bottom plate normally biased against the peripheraledge of said members, and

a check valve member internal of said hollow body positionedintermediate said conduit means and said outlet, said diffusers beingmounted vertically above said manifold.

1. A gas distribution nozzle comprising, in combination: a hollow bodyformed of a generally conical umbrella like member, said member beingclosed at its apex and open at the end opposite the apex of the conicalform to provide a gas outlet adjacent said open end, a relatively stiffbottom plate normally biased against the peripheral edge of said member;conduit means within said hollow body for connection to a source of gaspressure; and a check valve member internal of the hollow bodypositioned intermediate said conduit means and said outlet.
 2. The gasdistribution nozzle of claim 1 including a plurality of serrated openingformed in the peripheral edge of the umbrella-like member.
 3. The gasdistribution nozzle of claim 2 wherein the internal angle formed withinthe conical wall of the hollow body is relatively wide and the bottomplate is within the periphery of the conical member.
 4. The gasdistribution nozzle of claim 2 including a relatively resilient platesupported within the conical member inwardly of and adjacent said bottomplate, an annular ledge formed on the inner wall of the conical member,and means biasing the resilient plate against the annular ledge and saidbottom plate positioned to limit the movement of said resilient plateaway from said ledge.
 5. The gas distribution nozzle of claim 2 whereinsaid conduit means comprises a pipe protruding throu1h the bottom plateand having only circumferential openings and including a resilientsleeve fitted about the portion of the pipe having said openings so asto seal said openings whenever sufficient pressure does not exist toexpand said sleeve.
 6. A gas distribution system for providing oxidationand circulation within a fluid including: a tank; a source of gaspressure mounted proximate said tank; a manifold supported within saidtank and flow-coupled to said source through a conduit extendingtherebetween; a plurality of diffusers mounted on said manifold andhaving conduit means therein respectively adapted to be supplied with apressurized gas therefrom, each said diffuser comprising a hollow bodyformed of a generally conical umbrella-like member, said member beingclosed at its apex and open at the end opposite the apex of the conicalmember to provide a gas outlet adjacent said open end, a relativelystiff bottom plate normally biased against the peripheral edge of saidmembers, and a check valve member internal of said hollow bodypositioned intermediate said conduit means and said outlet, saiddiffusers being mounted vertically above said manifold.